Re: [net-next 11/13] igb: Make Tx budget for NAPI user adjustable

Jeff Kirsher
2011-09-19T23:36:44Z

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On Mon, 2011-09-19 at 15:27 -0700, Duyck, Alexander H wrote:
> On 09/19/2011 02:00 PM, David Miller wrote:
> > From: Alexander Duyck<alexander.h.duyck@intel.com>
> > Date: Mon, 19 Sep 2011 09:32:18 -0700
> >> The fact is ixgbe has been using this parameter this way for over 2
> >> years now and the main goal of this patch was just to synchronize how
> >> things work on igb and ixgbe.
> >>
> >> Our hardware doesn't have a mechanism for firing an interrupt after X
> >> number of frames so instead we simply have modified things so that we
> >> will only process X number of frames and then fire another
> >> interrupt/poll if needed. As such we aren't that far out of
> >> compliance with the meaning of how this parameter is supposed to be
> >> used.
> > All I can say is this was a huge mistake you therefore need to revert
> > the IXGBE change, these ethtool settings are not for changing NAPI or
> > software interrupt behavior.
> >
> > And if you guys plan to be difficult on this and refuse to remove the
> > IXGBE bits, I'm letting you guys know ahead of time that I'll do it
> > for you.
> >
> > If the hardware can't support this facility, neither should these
> > ethtool hooks, because the whole point is to avoid hardware interrupts
> > from firing using these parameters.
> >
> > Propose new mechanisms to control NAPI behavior if you want.
> I'll remove the ixgbe code if that is what you want. It may be a month
> or so before I can get to it though since I am slammed with work so if
> you are in a hurry for it you might want to work with Jeff Kirsher to
> have the code removed.

Alex- I will work on this to resolve the issues the Ben and Dave have
pointed out.

>
> As far as this current patch goes I honestly don't have the time to add
> or rewrite yet another ethtool interface so I will probably just see
> about dropping the ethtool portion of this patch and update the
> description in order to make it acceptable.
>
> Thanks,
>
> Alex

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